Development of NX211 (liposomal lurtotecan) is that liposomal encapsulation will prolong the plasma half life of lurtotecan in human subjects, resulting in prolonged tumor exposure, enhanced efficacy and an improved therapeutic index. Based upon pre-clinical data, it is believed that liposomal encapsulation may be more effective than free lurtotecan. Also, neutrophil and platelet counts on Day 8 will be satisfactory to proceed w/administration of the second dose of the cycle. SPECIFIC ENDPOINTS: 1) To evaluate the safety and tolerability of NX211 2) To establish the Dose Limiting Toxicities (DLT) of NX211 and to identify the recommended dose for Phase II studies 3) To evaluated the pharmacokinetic profile of NX211 4) To evaluated any anti-tumor activity in a preliminary manner 5) To assess, for descriptive pruposes, NX211 concentrations in tissue samples (tumor and adjacent normal tissue) in selected patients 6) A secondary objective is to determine whether or not NX211 crosses the blood-brain barrier -to evaluate the safety and tolerability.